Thats an everyday scene in London, it is such a cosmopolitan city and there are probably more smokers in London than many other UK cities combined.
We also have a fair share of drinkers, some of whom pass the time away oblivious to the real world.

I hope you enjoyed your trip to London and that you avoided the time when the "Idiots" were out to play.

I live about 2hrs from London so don't visit that often, I have always found it a great place for street shots but alas, the Police & Secuity men who look after many areas have become very anal over the past year and have challenged many people with cameras.

I trust you were able to get some interesting images without hassle, and I for one look forwards to seeing the results on here.